下伏土洞加筋地基条形荷载下应力扩散计算

通过大变形有限元分析,对下伏土洞加筋地基条形荷载下应力扩散的作用机理和沉降进行研究,分析了条形基础置于土体上的土体附加应力扩散、土洞区内应力及沉降变化规律。结果表明,土洞区内出现应力集中,下伏土洞地基沉降主要是由于土洞区内软弱土体变形造成。加筋体会增强应力扩散从而减小沉降,加筋体长度和埋深均存在最佳值;多层加筋较单层加筋更利于应力扩散,且层间会出现未完全拱形应力集中区域;相同加筋范围,层数增大对应力扩散影响较小,增大加筋范围更有助于应力扩散。     

一类三种群的捕食-被捕食弱耦合反应扩散生态系统解的渐近性态

研究了一类非线性三种群弱耦合捕食—被捕食反应扩散系统的初边值问题,在适当的条件下,利用反应扩散方程理论、多重尺度变量和微分中值定理,结合分析技巧,对此问题解的存在性及渐近性态作了较深入的研究,得到了问题解的存在性和一致有效性.     

Analytical solution for 1D consolidation of unsaturated soil with mixed boundary condition

Based on consolidation equations proposed for unsaturated soil, an analytical solution for 1D consolidation of an unsaturated single-layer soil with nonhomogeneous mixed boundary condition is developed. The mixed boundary condition can be used for special applications, such as tests occur in laboratory. The analytical solution is obtained by assuming all material parameters remain constant during consolidation. In the derivation of the analytical solution, the nonhomogeneous boundary condition is first transformed into a homogeneous boundary condition. Then, the eigenfunction and eigenvalue are derived according to the consolidation equations and the new boundary condition. Finally, using the method of undetermined coefficients and the orthogonal relation of the eigenfunction, the analytical solution for the new boundary condition is obtained. The present method is applicable to various types of boundary conditions. Several numerical examples are provided to investigate the consolidation behavior of an unsaturated single-layer soil with mixed boundary condition.     

一类Duffing型时滞微分方程的周期解

考虑Duffing型方程ax’’(t) f(x(t))x’(t) bx(t) g(x(t-(t)))=p(t),用重合度理论,获得了此方程至少存在一个2π周期解的充分条件。     

一类带扰动的算子包含解的存在性

在H ilbert空间中,利用集值压缩映象的不动点定理,讨论了一类带扰动的算子包含解的存在性.     

Relationships of personality,affect, emotional intelligence and coping with student stress and academic success: Different patterns of association for stress and success

The associations of personality, affect, trait emotional intelligence (EI) and coping style measured at the start of the academic year with later academic performance were examined in a group of undergraduate students at the University of Edinburgh. The associations of the dispositional and affect measures with concurrent stress and life satisfaction were also examined. The survey was completed by 238 students, of whom 163 gave permission for their end-of-year marks to be accessed. Complete data for modelling stress and academic success were available for 216 and 156 students respectively. The associations of academic success and stress differed, and high stress was not a risk factor for poor academic performance. Further analyses were based on the extraction of three composite factors (Emotional Regulation, Avoidance and Task Focus) from the EI and coping subscales. Structural equation modelling showed that academic performance was predicted by Conscientiousness, Agreeableness, positive affect and the Task Focus factor. Modelling for stress and life satisfaction showed relationships with personality, affect, and the Task Focus and Emotion Regulation factors. The Task Focus factor played a mediating role in both models, and the Emotion Regulation factor acted as a mediator in the model for stress and life satisfaction. The theoretical interpretation of these results, and their potential applications in interventions targeting at-risk students, are discussed.     

含有一个参数的一阶微分方程极值解的存在性

舍一个参数的一阶微分方程边值问题是指:含有未知量及它的一阶导数的方程的定解务件不仅依赖于在区间端点的取值,而且依赖于方程中的参数.通常它用不动点定理或逐步逼近法来解决.文章利用上下解方法和单调迭代技术讨论了含有一个参数的微分问题极值解的存在性,通过构造单调序列使这个单调序列一致收敛于非线性方程的极值解.     

具有分布滞量的微分方程的正周期解的存在性

通过使用Krasnoselskii锥不动点定理，研究了一类具有分布滞量的微分系统的正周期解的存在性。     

一类带扰动的算子方程组解的存在性和唯一性

给出乘积空间中的压缩映像原理,利用它在Hilbert空间中讨论一类带扰动的非线性算子方程组S（x,y）＋M（x,y）=0 T（x,y）＋N（x,y）=0（x,y）∈X1×X2解的存在性和唯一性.     

Best-bet channels for integrated soil fertility management communication and dissemination along the agricultural product value-chain: a comparison of northern Ghana and western Kenya

Purpose: The aim of this paper is to comparatively assess the most suitable channels for dissemination of agricultural innovations along the entire information value chain.

Design/Methodology/Approach: We calculated information scores to measure channel preference from a randomly selected sample of farmers: 285 in Tamale, Ghana and 300 in Kakamega, Kenya. Using t-tests we compared the information score differences of different channels between farmers who adopted Integrated Soil Fertility Management and those who did not.

Findings: The highest information scores were observed for radio along the entire value chain for both locations. However, farmers in Tamale prefered interpersonal channels for processing information. Radio and farmer field days had the highest rankings for production information at both locations. Radio, workshops and interpersonal channels (traders and neighbours/friends/relatives) were best-bet channels for marketing and procesing information.

Practical implication: Extension agents should place more emphasis on channels such as radio, farmer field days, and workshops as they may offer more efficient delivery of information packages at all levels, whilst recognizing the central role of interpersonal channels.

Theoretical implication: The nexus between the uses and gratification, adoption, diffusion of innovations theories and the collaborative communication theory on one hand, and the agricultural product value chain framework on the other, is highlighted. Farmers’ preference for information channels is not predicated on the stage of the value chain.

Originality/Value: In the current context of weak agricultural knowledge and innovation systems in African agriculture, agricultural producers are poorly informed about the current innovations. This study furnishes empirical evidence on the best-bet information channels to be used by extension workers and change agents to disseminate and communicate system innovations.     

一类相似组合系统分散自适应模糊控制

针对一类具有函数控制增益的非线性相似组合大系统,基于一种修改的李亚普诺夫函数并利用Ⅱ型模糊系统的通用逼近能力,提出了一种稳定自适应分散模糊控制器设计的新方案。该方案能够避免现有的一些模糊控制器设计中对控制增益一阶导数上界的要求。通过理论分析,证明了闭环分散模糊控制系统是全局稳定的,跟踪误差收敛到零。     

带阻尼项的(q,p)-Laplace问题周期解的存在性

利用临界点理论中的极大极小方法,通过引入一类控制函数,研究了带阻尼项的q,(p)-Laplace问题周期解的存在性,本文定理推广和发展了已有文献中的相关结果。     

创建有特色的“三位一体”高职技能教学模式

教育方针是国家教育工作的根本指导思想,也是指导教育教学改革的行动指南。重庆教育学院旅游系借重庆直辖的契机,努力践行教育方针,不断改革创新,抓住“两个结合”,在岗位技能课程教学中,将高职教学要求、岗位实际需求、国家职业标准三者相衔结,形成“三位一体”的教学模式的教改实践与探索,以期揭示符合市场要求具有高职特色的高职技能教学模式。     

具有Hardy项和Hardy-Sobolev临界指数的半线性椭圆方程正解的存在性及估计

本文用Ekeland变分原理证明了一类具Hardy项和Hardy-Sobolev临界指数的半线性椭圆方程正解的存在性,并用最大值原理对正解进行估计.     

Comprehensive reading instruction for students with intellectual disabilities: Findings from the first three years of a longitudinal study

This longitudinal experimental study investigated the reading progress of students with IQs ranging from 40 to 69 (i.e., range for students with mild or moderate mental retardation or intellectual disabilities [ID]) across at least two academic years, as well as the effectiveness of a comprehensive reading intervention for these students across the same period of time. Participants were 59 elementary students who were randomly placed into treatment and contrast groups. Students in the treatment condition received daily, comprehensive reading instruction in small groups of 1–4 students for 40–50 minutes per session across two or three academic years. Measures of phonemic awareness, phonics, word recognition, comprehension, and oral language were included. Findings indicate that students with IQs in the ID range made significant progress on multiple standardized measures of reading. Furthermore, significant differences between the treatment group and contrast group were found on several measures, including progress‐monitoring measures of phoneme segmentation, phonics, and oral reading fluency. Results demonstrate that, on average, students with ID, even those with IQs in the moderate range, learn basic reading skills given consistent, explicit, and comprehensive reading instruction across an extended period of time. © 2010 Wiley Periodicals, Inc.     

Science Letters：Evaluation of a kinetic uricase method for serum uric acid assay by predicting background absorbance of uricase reaction solution with an integrated method

A patented kinetic uricase method was evaluated for serum uric acid assay. Initial absorbance of the reaction mixture before uricase action （A0） was obtained by correcting the absorbance at 293 nm measured before the addition of uricase solution, and background absorbance （Ab） was predicted by an integrated method. Uric acid concentration in reaction solution was calculated from AA, the difference between A0 and Ab, using the absorptivity preset for uric acid. This kinetic uricase method exhibited CV〈4.3% and recovery of 100%. Lipids, bilirubin, hemoglobin, ascorbic acid, reduced glutathione and xanthine 〈0.32 mmol/L in serum had no significant effects. △A linearly responded to 1.2 to 37.5 μmol/L uric acid in reaction solution containing 15 μl serum. The slope of linear response was consistent with the absorptivity preset for uric acid while the intercept was consistent with that for serum alone. Uric acid concentrations in clinic sera by different uricase methods positively correlated to each other. By Bland-Altman analysis, this kinetic uricase method accorded with that by quantifying the total change of UV absorbance on the completion of uricase reaction. These results demonstrated that this kinetic uricase method is reliable for serum uric acid assay with enhanced resistance to both xanthine and other common errors, wider range of linear response and much lower cost.     

Identification of candidate genes for drought stress tolerance in rice by the integration of a genetic （QTL） map with the rice genome physical map

INTRODUCTION Drought stress is a major constraint to rice(Oryza sativa) production and yield stability in rainedecosystems (Dey and Upadhyaya, 1996). Rice mustbe made more drought tolerant, but this is a somewhatcontradictory objective considering that rice is mostcommonly grown under flooded conditions. Achiev-ing drought tolerance in rice will require a deeperunderstanding of the possible physiological mecha-nisms available for water stress tolerance and theidentification of favo…